Mold compound



Patented Jan. 26, 1926.

UNITED STATES PATENT OFFICE;

CHARLES E. LEHR, OF BETHLEHEM. PENNSYLVANIA. ASSIGNOR TO BETHLEHEM STEELCOMPANY.

MOLD COMPOUND.

No Drawing. I

To all whom it my concern:

Be it known that I. CHARLES E. LEHR, a citizen of the United States. andresident of Bethlehem, Lehigh County; State of Pennsylvania. haveinvented certain new and useful Improvements in Mold Comv pounds," ofwhich the following is aspecification.

This invention relates. to a mold or core material. The object, of theinvention is to revivify foundry sand by the addition of comminuted slagsuch as may be procured by the operation of a blast furnace. open hearthfurnace or the like. The slag is crushed or ground into fine partic esby any suitable apparatus and mixed with the inert sand together with asmall quantitv of fire clav, the latter ingredient constituting abinding medium so that the compound mav be formed into various shapes asrequired in foundry operations.

The invention contemplates a compound for forming molds having a highdegree of permeability to the passage of gases evolved in the casting.operation and. furthermore. provides a material havinghigh refractorvproperties. which prevent the material from burning fast to the castingsand avoids the formation of scabs thereon.

to I have found that a mixture consisting of approximately four partscomminuted" slag and one part silica sand with a small percentage offire clay provides a very desirable material for making molds ,or cores85 for the casting of metals.

While the principal object of my invention is to provide a compound forrevivifying sands usually employed in foundry practice. nevertheless. itshould be under- 40 stood that my' invention further contemplates theuse of new sa'nd as one ofthe constituents of my mixture.

It is customary in foundry operations, particularly steel foundrypractice, to use 40 to of new sand incorporated with old sand whenforming molds, due to sand becoming inert by the burning out of thevegetable matter and the fusing of the low a grade fire clay-which itcontains. I I In accordance with my invention, 1- use comminuted slag.This ingredient is not Application filed May 27, 1925. Serial No.38,287.

only cheap. being ordinarily a waste byproduct of blast or open hearthfurnace operation, but it also gives a degree of stability to the moldor core mixture. the latter result being due to the fibrous nature orcharacteristic of the slag.

As already pointed out. I prefer to prepare a mixture consisting ofapproximately four parts of comminuted slag and one part of sandcontaining a-suificient amount of argillaceous material. If the sand isnew, there may be sufiicient vegetable and clav matter to form a binder;however. with use. sand becomes inert. the vegetable mat-.

ter burning out and the clay fusing. and, Vlilllll old sand, I add asmall amount of fire c av.

From the foregoing, it will be apparent that I have provided a mixturewhich greatlv reduces the requirements for new sand for the reason therevivifying effect of my comminuted slag and .fine clay additionspermits of sand being used over and over agam. Another advantageousfeature'fis opening up a new field of use for a waste product. namelv.slag: and owing to the abundance of slag. the cost of foundry operations may be greatlv reduced. In addition to the economic advantagesjust pointed out. mv composition is advantageous from the phvsicalpoints of view of stabilfoundry molds comprising comminuted slag andsilica sand.

3. A compound suitable for formm foundry molds comprising commmute slag,inert foundry'sand and fire clay.

4. A compound suitable for formmgi foundry molds comprising comminutedmetallurgical slag, silica sand and fire clay.

5. A compound suitable for forming foundry molds comprising about fourparts I comminuted slag, and about onepartfoundry sand.

6. A compound suitable for forming foundry molds comprising about fourparts comminuted slag, about one part foundry sand and a smallpercentage of fire clay.

In testimony whereof I hereunto aifix my signature this 22nd day of May,1925.

CHARLES E. LEHR.

